Effects of integrin alpha IIb(R995A) mutation on receptor affinity and pp125 (FAK) phosphorylation.
- Author:
Xue-yuan TANG
1
;
Zai-fu JIAN
;
Guo-ping WANG
;
Hong-hui YANG
;
Wei LIU
Author Information
- Publication Type:Journal Article
- MeSH: Animals; Blood Platelets; metabolism; CHO Cells; Cell Adhesion; Cricetinae; Cricetulus; Cytoplasm; metabolism; Dual Specificity Phosphatase 2; Focal Adhesion Kinase 1; Focal Adhesion Protein-Tyrosine Kinases; Humans; Phosphorylation; Platelet Glycoprotein GPIIb-IIIa Complex; genetics; metabolism; physiology; Point Mutation; Protein Phosphatase 2; Protein Tyrosine Phosphatases; metabolism; Protein-Tyrosine Kinases; metabolism; Signal Transduction; Transfection
- From: Chinese Medical Sciences Journal 2004;19(4):276-281
- CountryChina
- Language:English
-
Abstract:
OBJECTIVETo investigate the role of cytoplasmic domain of integrin alpha IIb in platelet signal transduction.
METHODSBinding capacity of integrin alpha IIb(R995A) to antibody platelet activation complex-1 (PAC-1) and pp125 focal adhesion kinase (FAK) phosphorylation of cells were detected by flow cytometry, immune precipitation, and Western blotting.
RESULTSWithout activation, wild-type alpha IIb beta3 Chinese hamster ovary (CHO) cells failed to bind to PAC-1, but mutant chimera alpha IIb(R995A)beta3 CHO cells were able to bind with PAC-1. Furthermore, phosphorylation of pp125 (FAK) in wild-type alpha IIb beta3 CHO cells occured only when cells were adhered to fibrinogen, but could not be detected in bovine serum albumin suspension. However in the mutant chimera group, it could be detected in both conditions.
CONCLUSIONThe mutation in integrin alpha IIb(R995A) alters its affinity state as a receptor, thus also mediating cytoplasmic signal transduction leading to the phosphorylation of pp125 (FAK) without ligand binding.
